INTRODUCTION
Granulomatous mastitis (GM) is a rare, poorly characterized inflammatory disease with a broad differential diagnosis that includes both benign and malignant conditions such as infectious mastitis, sarcoidosis, and inflammatory breast cancer.1,2,3 The etiology of most cases is idiopathic (IGM).1 In this retrospective study, we present our experience of 31 patients with IGM, underscoring management and treatment outcomes.
The study was approved by the institution review board of Massachusetts General Hospital. We selected patients with suspected GM referred to our rheumatology-dermatology clinic (where these patients are seen at our institution) between 2012 and 2020 using ICD10 code N61.2 in Epic electronic medical record and clinic schedules. The patients were seen by either a dermatologist with a rheumatologist or dermatologist alone depending on scheduling availability. Treatment and clinical outcomes were extracted from chart reviews. Recommended workup and treatment regimens were similar between specialists and patients were given a diagnosis of IGM once other causes of mastitis were ruled out. Initial treatment, defined as the regimen implemented at the first visit, and initial response were evaluated within 3 months of therapy. Subsequent treatments were those introduced after the first 3 months and subsequent response was assessed 6 or more months after the initial visit. We defined treatment response as partial if there was improvement in clinical characteristics (such as erythema and swelling) or complete if all symptoms resolved. No response refers to no improvement in clinical symptoms. Clinical response and treatment outcomes are summarized in Tables 1 and 2.
The study was approved by the institution review board of Massachusetts General Hospital. We selected patients with suspected GM referred to our rheumatology-dermatology clinic (where these patients are seen at our institution) between 2012 and 2020 using ICD10 code N61.2 in Epic electronic medical record and clinic schedules. The patients were seen by either a dermatologist with a rheumatologist or dermatologist alone depending on scheduling availability. Treatment and clinical outcomes were extracted from chart reviews. Recommended workup and treatment regimens were similar between specialists and patients were given a diagnosis of IGM once other causes of mastitis were ruled out. Initial treatment, defined as the regimen implemented at the first visit, and initial response were evaluated within 3 months of therapy. Subsequent treatments were those introduced after the first 3 months and subsequent response was assessed 6 or more months after the initial visit. We defined treatment response as partial if there was improvement in clinical characteristics (such as erythema and swelling) or complete if all symptoms resolved. No response refers to no improvement in clinical symptoms. Clinical response and treatment outcomes are summarized in Tables 1 and 2.
